To save weight, cut energy use, steering has no power assist. Seats adjust manually. Windows crank up and down by hand. Small blue rectangle left of steering wheel is video screen showing rear view from an outside camera. Volkswagen

Passenger seat is mounted further back than driver's seat, and and overlaps driver's seat a bit to allow the car to be narrower. That cuts wind resistance. In previous iterations, the passenger sat directly behind the driver. Volkswagen

The XL1's scissor doors open wide and high into the roof, but the car's low height and high door sills still make it an effort to get in and out. The offset passenger seat sits far enough back that it's hard to reach the pull-down handle. Fred Meier, USA TODAY

Volkswagen's XL1 uses a 0.83-liter two-cylinder diesel and an electric motor, mated to a seven-speed automatic like the one used in the Jetta hybrid. The car's only available in Germany.(Photo: Volkswagen)

A car company without a new model to promote is a sad thing. Sales fall. Morale slips. Dealers grumble.

Volkswagen's in that limbo. Nothing new until first quarter next year, when the seventh-generation Golf subcompacts start rolling in here from VW's new operation in Mexico.

When VW is in a dead spot, though, it rotates sexy and unobtainable overseas models through the U.S. test fleet. Helps keep the easily distracted media's attention off the aging model lineup and lackluster sales.

More seriously, it provides a look at VW expertise otherwise unseen here. And it tests U.S. reactions to various models.

Thus, the small Up last year, after a World Car of the Year win. Also the Scirocco sport coupe and diesel Tiguan SUV this year. For the record, Up is a keen little car that might do OK in the U.S. Scirocco is terrific to drive. And the diesel seems like exactly the right engine for the Tiguan.

The latest teaser: XL1. It's a spaceship-like, ultra-high-mpg, plug-in diesel-electric hybrid. VW used exotic, but obtainable, materials and technologies to craft a mileage-above-all car able to get 261 mpg in European tests, equating, very roughly, to perhaps 200 mpg in U.S. tests.

Barely a real production model, it's made in a factory, but largely by hand. It couldn't meet U.S. safety rules and needed changes in German rules to be on the road there.

But it shows how fuel-thrifty a car can be and still perform OK.

Just 50 have been sold in Germany, another 200 are planned. The price is 111,000 euro, or about $151,000 at recent rates.

Lightweight and aerodynamic slipperiness are keys to minimum fuel consumption. So there is little to no sound insulation, cutting weight. Manual steering instead of power steering cuts weight as well as energy use. A layered-wood dashboard isn't as heavy as other materials. The vestigial fuel tank holds 2.6 gallons of diesel. Side windows are plexiglass and crank by hand. The XL1 is just 45.4 inches high and weighs in at just 1,753 pounds.

It's derived from two previous VW high-mpg efforts, called L1. Big change from those: XL1's two occupants sit nearly side-by-side instead of ahead-and-behind in the previous models. That makes the XL1 a bit wider, bad for aerodynamics, but the seats are offset with the passenger back and overlapping the driver's seat a little to keep the car narrow.

With the help of unindicted co-conspirators we were able to snatch away the XL1 on tour and enjoy an afternoon of suburban bee-bop.

Draws lots of attention. All want to know the same thing: What is that?

The small size and ground-hugging stance means getting in and out is awkward, even though the scissors doors swing up for a big opening. Lack of sound deadening means you can hear the tires slap every bump and the diesel respond to every throttle movement.

While the diesel clattered enough to force occupants to raise their voices, we almost grew to like it. A reassuring reminder that the minuscule engine won't let you down.

Won't thrill you, though. About 12.7 seconds to hit 60 mph, VW says. Usually anything more than about nine seconds is judged sluggish. But you sit so close to the ground that it seems to be whipping past under wide-open throttle. Sluggishness isn't the overriding impression, no matter what the stopwatch says.

One reason for that is the seven-speed dry-clutch automatic transmission. It's like the one in the Jetta hybrid, showing the XL1 isn't made entirely of exotic components. Works great, snipping up through the gears, or down, with little interruption.

The diesel and electric powerplants are well integrated. If you couldn't hear the diesel, it'd be tough to notice when the car switches among drive modes.

Of course, no car slated for mass production would be as noisy, but VW is trying to prove what's possible, not necessarily practical.

The sleek roof provides no rear window. Equally sleek sides aren't interrupted by mirrors. Rear view is via two cameras in tiny pods about where mirrors would be. Inside, each door has a view screen in which to see what's beside and behind.

It would take us longer to get used to the camera system than it would to get comfortable with the noise.

A car without mirrors — you can begin to see the kinds of regulatory hurdles the XL1 would have to jump to become mainstream. Just one air bag, in the steering wheel. Another non-starter almost everywhere.

It's not a big problem going without power steering. Not only is the car light, it rides on tires closer to rubber bands than traction devices. Front tires are 155 mm wide and rears are 145 mm, so not a lot of road contact to overcome. Even very small cars have closer to 200-mm tires.

The steering feel is a bit heavy when barely moving, but has a refreshing directness once underway.

XL1 is valuable for starkly illustrating the trade-offs between fuel use and practicality. It's heartening to see that a car with a more-or-less conventional powertrain can use so little fuel, while providing marginally street-worthy transportation.

It's less cheery to think of how long it might take to come up with affordable materials even lighter than used in XL1 so the car could have the accessories and other weightier features that today's buyers expect.